Sure you can. You simply email one of the listed authors and ask them if the document is legit.
Nothing about any of this is new or profound. Counterfeit documents have been around for hundreds of years.
Their point (I assume) was that it would be illogical to worry that the report might be written and released by AI yet consider an email response as evidence against it.
If AI can create and release this report it can also hijack a real person's email or create a fake persona that pretends to be a real person.